The present invention relates an essential oil product obtained from the Morinda citrifolia plant and to the process of extracting and purifying the oil.
The Indian Mulberry plant, known scientifically as Morinda citrifolia L., is a shrub, or small or medium sized tree 3 to 10 meters high. It grows in tropical coastal regions around the world. The plant grows randomly in the wild, and it has been cultivated in plantations and small individual growing plots. The Indian mulberry plant has somewhat rounded branches and evergreen, opposite (or spuriously alternate), dark, glossy, wavy, prominently-veined leaves. The leaves are broadly elliptic to oblong, pointed at both ends, 10-30 cm in length and 5-15 cm wide.
The Indian mulberry flowers are small, white, 3 to 5 lobed, tubular, fragrant, and about 1.25 cm long. The flowers develop into compound fruits composed of many small drupes fused into an ovoid, ellipsoid or roundish, lumpy body, 5-10 cm long, 5-7 cm thick, with waxy, white or greenish-white or yellowish, semi-translucent skin. The fruit contains xe2x80x9ceyesxe2x80x9d on its surface, similar to a potato. The fruit is juicy, bitter, dull-yellow or yellowish-white, and contains numerous red-brown, hard, oblong-triangular, winged, 2-celled stones, each containing 4 seeds.
When fully ripe, the fruit has a pronounced odor like rancid cheese. Although the fruit has been eaten by several nationalities as food, the most common use of the Indian mulberry plant was as a red and yellow dye source. Recently, there has been an interest in the nutritional and health benefits of the Indian mulberry plant.
It would be a significant advancement in the art to provide the essential oil from the Indian mulberry plant and to provide a process for obtaining the essential oil from the Indian mulberry plant.
The present invention is directed to an essential oil extracted from Indian mulberry (Morinda citrifolia) seeds and to a process of extracting the oil. The Indian mulberry oil typically includes a mixture of several different fatty acids as triglycerides, such as palmitic, stearic, oleic, and linoleic fatty acids, and other fatty acids present in lesser quantities.
The essential oil preferably includes an antioxidant to inhibit spoilage of the oil. Conventional, food grade antioxidants are preferably used, including, but not limited to, tocopherol acetate (vitamin E acetate), propyl gallate, TBHQ (t-butyl hydroquinone), BHT (3,5-bis(t-butyl)-4-hydroxytoluene), and French maritime pine bark extract.
The process for extracting Indian mulberry oil from its seeds typically involves obtaining Indian mulberry seeds that are dried to a moisture content less than 10%, by weight, and preferably from 5% to 8%, by weight. The seeds are cracked, ground, or reduced in size, typically from 2 to 20 mm. The flaked seeds are then pressed in a mechanical press or screw press to expel some of the oil. The remaining seed cake is mixed with a nonpolar extraction solvent. The extraction solvent is preferable food-grade. One currently preferred nonpolar solvent is hexane.
Oil extraction with the nonpolar solvent preferably takes place at a temperature range between 80xc2x0 F. and 200xc2x0 F. and ranges from a time of 30 minutes up to 12 hours. It is presently preferred to complete the extraction step as quickly as possible. The nonpolar solvent is preferably removed from the extracted oil through flash evaporation.
The oil from the mechanical press and from the nonpolar solvent extraction may be combined or further refined separately. The refining process removes impurities from the oil. Caustic, water, and phosphoric acid can be added to the oil to precipitate impurities. The precipitating agents and oil are mixed and heated to a temperature between 100xc2x0 F. and 200xc2x0 F., the currently preferred target temperature is between 170xc2x0 F. and 180xc2x0 F. The mixture is centrifuged to remove precipitated impurities that include, but are not limited to, insoluble gums, phosphatides, and free fatty acids.
The oil can optionally be further refined by bleaching and deodorizing. Bleaching involves the addition of one or more filtering agents to the oil. The oil is filtered through a mechanical filter to remove the filtering agents. Currently preferred filtering agents include diatomaceous earth (D.E.) and activated charcoal. Bleaching removes color bodies and soap materials generated during the refining process. Bleaching is preferably done at temperatures between 100xc2x0 F. and 200xc2x0 F.
The oil may or may not be vacuumed dried to remove any residual water. The oil is deodorized to remove volatile impurities. This involves steam distillation under a vacuum and at temperatures between 300xc2x0 F. and 500xc2x0 F. An antioxidant can be included with the extracted oil, as mentioned above.